The objective of this research is to gain further understanding of the molecular mechanisms underlying development and differentiation. The fundamental theme will be the elucidation of the means operating in the early embryogenesis for regulating the use of genetic information. Sea urchins will be used as a model embryonic system. The importance of the maternal templates for supporting the activation of protein synthesis that occurs at fertilization will be determined and compared to the involvement of new templates in this stimulation process. It is not known how the usage of maternal and new templates is integrated. This will be investigated by a careful examination of some specific proteins that are synthesized in the cleaving embryo, especially the histones, microtubular proteins and some enzymes on the pathway to DNA synthesis. The amount of synthesis of these proteins under the direction of maternal and new RNA will be assayed as a means of determining the mode of regulation involved in their synthesis. Translational level control of protein synthesis will also be studied through an examination of the efficiency of supernatant factors and of ribosomes in eggs, and developing embryos. There is undoubtedly a change in the program of RNA synthesized during development, and we are initiating studies into relating this change to variations in the chemical composition and template properties of isolated chromatin from developing embryos.